On 07/20/2017 09:49 AM, Masahiro Yamada wrote:
2017-07-20 2:33 GMT+09:00 Marek Vasut marex@denx.de:
On 07/19/2017 05:38 PM, Masahiro Yamada wrote:
2017-07-15 21:57 GMT+09:00 Marek Vasut marex@denx.de:
On 07/15/2017 01:30 AM, Benoît Thébaudeau wrote:
On Sat, Jul 15, 2017 at 12:06 AM, Marek Vasut marex@denx.de wrote:
On 07/14/2017 11:46 PM, Benoît Thébaudeau wrote: > On Fri, Jul 14, 2017 at 1:50 PM, Marek Vasut marex@denx.de wrote: >> On 07/14/2017 01:03 PM, Masahiro Yamada wrote: >>> 2017-07-14 19:07 GMT+09:00 Marek Vasut marex@denx.de: >>>> On 07/14/2017 04:31 AM, Masahiro Yamada wrote: >>>>> Prior to DM, we could not enable different types of USB controllers >>>>> at the same time. DM was supposed to loosen the limitation. It is >>>>> true that we can compile drivers, but they do not work. >>>>> >>>>> For example, if EHCI is enabled, xHCI fails as follows: >>>>> >>>>> => usb read 82000000 0 2000 >>>>> >>>>> USB read: device 0 block # 0, count 8192 ... WARN halted endpoint, queueing URB anyway. >>>>> Unexpected XHCI event TRB, skipping... (3fb54010 00000001 13000000 01008401) >>>>> BUG: failure at drivers/usb/host/xhci-ring.c:489/abort_td()! >>>>> BUG! >>>>> ### ERROR ### Please RESET the board ### >>>>> >>>>> The cause of the error seems the following code: >>>>> >>>>> #ifdef CONFIG_USB_EHCI_HCD >>>>> /* >>>>> * The U-Boot EHCI driver can handle any transfer length as long as there is >>>>> * enough free heap space left, but the SCSI READ(10) and WRITE(10) commands are >>>>> * limited to 65535 blocks. >>>>> */ >>>>> #define USB_MAX_XFER_BLK 65535 >>>>> #else >>>>> #define USB_MAX_XFER_BLK 20 >>>>> #endif >>>>> >>>>> To fix the problem, choose the chunk size at run-time for CONFIG_BLK. >>>> >>>> What happens if CONFIG_BLK is not set ? >>> >>> USB_MAX_XFER_BLK is chosen. >> >> And can we fix that even for non-CONFIG_BLK ? >> >>>> Why is it 20 for XHCI anyway ? >>> >>> You are the maintainer. >>> (I hope) you have better knowledge with this. >> >> Heh, way to deflect the question. I seem to remember some discussion >> about the DMA (?) limitation on XHCI, but I'd have to dig through the ML >> archives myself. >> >>> Looks like the following commit was picked up by you. >> >> 5 years ago, way before DM was what it is today . > > And even way before the introduction of XHCI into U-Boot, which means > that this 20 was targeting OHCI or proprietary HCDs, not XHCI. > USB_MAX_READ_BLK was already set to 20 in the initial revision of > usb_storage.c. As I said in the commit message, this 20 was certainly > not optimal for these non-EHCI HCDs, but it restored the previous > (i.e. pre-5dd95cf) behavior for these HCDs instead of using the 5 * 4 > KiB code, which was specific to ehci-hcd.c at that time. Without > knowing the rationale for the legacy 20 blocks, the safest approach > for non-EHCI HCDs was to use this value in order to avoid breaking a > platform or something. Looking at ohci-hcd.c, it limits the transfer > size to (N_URB_TD - 2) * 4 KiB, with N_URB_TD set to 48, so the > maximum number of transfers would depend on the MSC block size. > dwc2.c, isp116x-hcd.c, r8a66597-hcd.c, and sl811-hcd.c do not seem to > have any limit caused by these drivers. The limit with the current > XHCI code seems to be 64 * 64 KiB. So, nowadays, USB_MAX_XFER_BLK > could be set to 65535 for all HCDs but OHCI and XHCI, which require > specific rules depending on the MSC block size.
For whatever reason, something tells me that setting the block size to 64k for XHCI broke things, but I cannot locate the thread. But there's something in the back of my head ...
Indeed: according to what I said above, USB_MAX_XFER_BLK cannot be set to 65535 for XHCI. With an MSC block size of blksz = 512 bytes / block, USB_MAX_XFER_BLK can be set to at most 1 segment * (TRBS_PER_SEGMENT = 64 TRBs / segment) * (TRB_MAX_BUFF_SIZE = 65536 bytes / TRB) / blksz = 8192 blocks for XHCI. And for OHCI, the limit is (N_URB_TD - 2 = 46 TDs) * (4096 bytes / TD) / blksz = 368 blocks. The buffer alignment may also have to be taken into account to adjust these values, which would require a USB_MAX_XFER_BLK(host_if, start, blksz) macro or function. USB_MAX_XFER_BLK can however be set to 65535 regardless of blksz for all the other HCDs (i.e. EHCI, dwc2.c, isp116x-hcd.c, r8a66597-hcd.c, and sl811-hcd.c).
That's probably what I was looking for, thanks.
So, how shall we handle this?
If somebody can fix this in a correct way, I am happy to hand over this.
Any way to fix it for !CONFIG_BLK ?
common/usb_storage.c is sprinkled with ugly #ifdef CONFIG_BLK
IIUC, !CONFIG_BLK code will be removed after migration.
Is it worthwhile to save !CONFIG_BLK case?
Hmmmmmm, sigh. When is the migration happening, how far is it ?